Method and apparatus for preventing snow and ice accumulation



April 23, 1968 c. NEMMAIER ETAL 3,379,372

MET OD AND APPARATUS FOR PREVENTING SNOW AND ICE ACCUMULATION Filed Feb. 26, 1965 5 Sheets-Sheet 1 Christian Nemmaier 8 Peter Mario Amunn BY w W ATTORNE Y INVENTORS F I G. 2

April 23, 1968 c. NEMMAIER ETAL 3,379,372

METHOD AND APPARATUS FOR PREVENTING SNOW AND ICE ACCUMULATION 3 Sheets-Sheet 2 '"e'i Feb. 26, 1965 FIG.3.

FIG .4.

INVENTORS Christian Nemmuier 8 Peter Mono 'Amurm BY ATTORNEY April 23, 1968 c. NEMMAIER ETAL 3,379,372

METHOD AND APPARATUS FOR PREVENTING SNOW AND ICE ACCUMULATION Filed Feb. 26, 196 5 Sheets-Sheet 5 INVENTORS Peter Mario Amunn AT TORNE Y Christian Nemmaier 8 3,379,372 METHSD AND APPARATUS FOR PREVENTING NOW AND ME ACCUMULATHON Christian remmaier, Steinhoering-Ahersdorf, and Peter Mario Amann, Kempten, Germany, assignors to Eisenwerh Friedrich Schroeder, Munich, Germany Fiied ideh. 2c, 1965, Ser. No. 435,457 13 Claims. (Qi. 239-7) ABSTRAT OF THE DESCLGSURE A method and apparatus for coating a road surface with an even, adherent coating of a salt slurry having a high viscosity and an amount of water therein which is considerably less than the amount needed to form a saturated liquid solution whereby the formation of ice and accumulation of snow is deterred and the removal thereof is facilitated, with a minimum of loss of salt.

The spraying of dry, granular salt which may be heated to expedite the melting process is a well-known method to fight snow and ice on road surfaces. These known methods, however, do not always produce the desired effect and in addition are not very economical.

If granular salt is used, to which agents may be added which keep the grains from sticking together and also ensure storability and sprayability, it is e.g. virtually impossible to pretreat dry road surfaces which is especially important during periods of changing weather when snow is expected or the roads may become icy. The sprayed-on salt is easily swept aside by the draft caused by passing cars. Wind may also blow the salt away after it has been scattered on the road. For the same reasons a desirable spray pattern, i.e., an even distribution of the salt, cannot be provided if the dry salt is deposited on dry roads. The effect which traffic has on the pattern of deposition is not quite as disadvantageous if the dry salt is sprayed on snowy or icy roads since the melting process starts after a very short while. However, if it is windy while the salt is being sprayed, the spread pattern will be affected unfavorably and the deposition will not be fully efiective.

Pretreatment of dry road surfaces is possible if salt is sprayed in the form of brine. In this case, however, a loss of brine cannot be prevented since a certain amount will run off the roads, following the lengti and/or crosswise slopes commonly provided on road surfaces which are necessary to drain the road surfaces. Consequently, this method of pretreating dry road surfaces is also not very efficient. In addition, it is even less economical than the use of dry salt because larger amounts of salt are needed per surface unit if brine is sprayed instead of dry salt.

It is, therefore, an objective of the present invention to remedy these shortcomings and to prepare and apply the salt in such a manner that efiicient pretreatment of dry road surfaces is possible; it also aims at doing away with interference with the spray pattern by outside influences such as cross winds and drafts caused by passing cars. The invention solves this problem by adding a certain amount of water to the salt while it is sprayed which is considerably less than the amount needed to form a liquid saturated solution. The resulting sludge is then sprayed onto the road surface by means of a suitable spraying device.

In addition, the salt maybe pretreated by grinding it to a flour or powder consistency before or during the actual spraying process. Such pulverized salt yields a highly homogeneous sludge with small amounts of water.

The main advantages of the new process as compared to the known processes are that it is more economical States Patent ice and that the salt sludge adheres firmly to the road surface on which it is sprayed by the spraying device, permitting a perfect pretreatment of road surfaces. Other disadvantages present with the known processes of spraying and salt application can also be avoided. Thorough tests have also proven that the application of salt in the form of sludge tends to form an even salt pattern on the road which is hardly disturbed by flowing traflic, even if applied to a dry road surface; if disturbed at all the salt sludge will mainly be shifted only lengthwise while still maintaining an even pattern by the wheels of passing vehicles and will be rolled on smoothly as long as it does not convert into a film which adheres firmly to the road surface. Another advantage is that salt sludge applied to snowy or icy road surfaces induces the melting process more rapidly than does dry salt.

It is another objective of the present invention to provide suitable apparatus for the deposition of the salt sludge.

Other objectives and the nature and advantages of the present invention will be apparent from the following descriptions taken in conjunction with the accompanying drawings, wherein:

FIG. 1 shows a longitudinal section of a spraying device for salt sludge;

FIG. 2 shows another embodiment in longitudinal section;

FIGS. 3 and 4 show details of the spraying device of FIG. 2 as a cross section and as a top view, respectively;

FIG. 5 represents the cross section of a detail of the apparatus;

FiGS. 6 and 7 show further embodiments of the detail of FIG. 5.

Apparatus for spraying the salt sludge in accordance with the embodiment of FIG. 1 may comprise a container 2 which is mounted on a vehicle 1. The container can be firmly attached to the vehicle or it can be detachable. The container 2 serves as a receptacle for the salt sludge which, accordin to the invention, is constantly stirred before it is actually sprayed, i.e., before the salt is applied to the road surface by the spraying device. For this purpose the container 2 is equipped with an agitator 3 having an agitator shaft which may be vertical. The shaft 3 may be provided wih a screw 13 and a mixer blade or disc 14. The agitator is driven by a motor 4. A feed pipe 6 leads from an exit 15 of the container 2 to the surface to be treated. The model shown in FIG. 1 ha a vertical feed pipe. The feed pipe 5 has an adjustable stop valve 5 adjacent the exit 15 which can be set to either prevent salt sludge from entering into the feed pipe 6 or to permit a certain amount of sludge to pass through. If the stop valve is open, the sludge flows through the feed pipe into an open ended spray cup 8. The latter is coaxially arranged with the feed pipe 6 and can be rotated by a motor it). The spray cup 3 is fitted with a distributor disc 7 having slots 9 therein for the passage of the salt sludge therethrough. The disc '7 connects with the inner walls of the spray cup 8. When the spray cup begins to rotate, the sludge, partly through gravity and partly through centrifugal force, flows to the lower edge of the spray cup from where it is sprayed off. The shaft 11 driving the spray cup can be fitted with a feed screw 12 to guarantee a particularly smooth and continuous flow of salt sludge. Spray density and spray range can be adjusted by the motor 16 which can be set to drive the shaft 11 at varying speeds and by the distance of the lower edge of the spray cup from the road surface which can be set at various heights.

2 shows a model which differs from the model of FIG. 1 mainly in the way of admixing water which is done in the model of FIG. 2 wholly or partly just before spraying.

Container 22 which may be either permanently attached to the vehicle 21 or may be detachable is filled with either dry or slightly wct salt. This salt is fed to the spray cup by means of a feed screw 23 and a chute 24. A tanlr 25 is mounted over the container 22 containing water, or, to prevent freezing, a saturated salt solution. The liquid in the tank 25 also flows to the spray cup 23 through a drain pipe 26 and a control valve 27. A discharge nozzle 29 is at the lower end of the drain pipe 26.

The spray cup is essentially the same as the one described with respect to the embodiment of FIG. 1, but diiiers from it to the extent that it has two separate feed pipes extending thereto instead of one which is centrally located. Salt and liquid are mixed at the inner wall of the spray cup, the mixture flows down and is sprayed off at the edge. If the salt is to be initially soaked in the container 22 to the extent where it acquires a viscous consistency, as is advisable in the case of powderizcd salt, e.g., a sludge pump may be provided instead of the feed screw 23. A proportioning pump can be used instead of the control valve 27 to regulate the feed of water or salt solution from container 25 to the spray cup 28.

FIGS. 6 and 7 show particularly useful spray cup embodiments 38 and 48, respectively.

It is desirable to hold the spray surface or lower edge of the spray as close to the road surface as possible while the sludge salt is sprayed; e.g., if the lower edge of the spray cup is held at a 10 cm. distance from the road sur' face, the spray travels a distance which is less than the tire thickness of a small car. This means that a car directly beside the salt sludge sprayer will not be sprayed and can safely stand next to a salt sprayer without running the risk of damage to parts susceptible to corrosion. However, with such low clearance there is the danger of damaging the spray cup if the road is bumpy or if foreign matter is encountered on the road. It is therefore advisable to make the spray cup of flexible material, such as rubber or PVC, or to make portions thereof of such materials as shown in FIGS. 6 and 7. Reinforcing bands, e.g., with a wire insert, may be provided at the upper and at the lower end of the cup. Sheet steel rings can also be fitted to or molded in the lower portions of the spray cup (FIGS. 6 and 7). In this case it is helpful to sharpen the lower rim 39, 49 of the sheet steel rings 37, 47 to obtain a very fine structure of sprayed 01f droplets.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. The method of treating a road surface to deter the accumulation of snow and ice comprising the steps of:

wetting dry salt by adding a liquid only to the extent of producing a wet fluent adherent slurry having a high viscosity, the amount of liquid therein being considerably less than the amount needed to form a saturated solution; and dispersing said adherent viscous slurry onto said road surface as a substantially even salt pattern adhering substantially in its entirety to the road surface whereby runoff and/ or free salt losses are maintained at a minimum.

2. The method as claimed in claim 1 including the step of constantly agitating said slurry of salt prior to dispersion.

3. The method as claimed in claim 1 including the step of further diluting the slurry immediately before the slurry is dispersed onto said road, the amount of dilution being such that the high viscosity and adherent qualities are retained.

4, 4. The method as claimed in claim 1 including the step of initially pulverizing said salt into a pulverulent finely divided powder before adding said amount of liquid to form the adherent slurry. 5. The method as claimed in claim 1 including the step of gravity discharging said adherent slurry to a height above said road surface and centrifugally discharging the slurry in a spray onto the road surface to which it is to adhere.

6. Apparatus for depositing salt sludge comprising a container adapted to contain wet salt; a vehicle to carry said container; at frusto-conical spray-cup below said container; means to pass said salt from said container to said spray-cup; means to rotate said spray-cup about its vertical axis at variable speeds, said container being adapted to retain a salt sludge; an agitator in said container for mixing said sludge; wherein said means to pass said salt sludge from said container comprises a feed pipe and an adjustable stop valve; and wherein said spray cup further comprises a slotted distribution disc connected to the inner frusto-conical wall of said spray cup.

7. Apparatus in accordance with claim 6 comprising means to drive said agitator on a vertical axis; and wherein said feed pipe is coaxial with said spray cup.

8. Apparatus for dispersing salt slurry as an adherent layer comprising:

a vehicular container for containing a salt slurry, and

means communicating with said container for dispersing said slurry as an even adherent layer,

means in said container for agitating the slurry in the container,

said means for dispersing the slurry comprising a vertically disposed feed pipe communicating at the upper end with said container, and a frusto-conical spray cup having the larger end opening downwardly and the upper end communicating with said feed pipe, means for rotating said spray cup about a vertical axis of rotation, said cup including a slotted, integral disc disposed above the lower edge of said cup whereby the slurry is centrifugally discharged outwardly as it gravitates down the inner surface of said cup.

9. The structure as claimed in claim 8 in which said means for dispersing said slurry comprises an elongated, helical feed screw.

10. The structure as claimed in claim 9 in which said helical feed. screw is disposed vertically within said feed pipe.

11. The structure as claimed in claim 9 including auxiliary slurry-diluting means including a supply tank having a nozzle opening above the upper surface of said integral disc.

12. Apparatus in accordance with claim 8, wherein said frusto-conical wall of said spray cup is formed of flexible material.

13. Apparatus in accordance with claim 12, wherein said flexible frusto-conical wall comprises a sheet metal band at its lower portion, said band having a sharpened lower edge.

References Cited UNiTED STATES PATENTS 490,900 1/1893 Collins 239-156 1,751,531 3/1930 Schars 239--156 69 2,192,320 3/1940 McCarthy 37-495 FOREIGN PATENTS 291,227 4/1916 Germany.

70 M. HENSON WOOD, JR., Primary Examiner.

ABRAHAM G. STONE, Examiner.

J'. R. OAKS, H. NATTER, Assistant Examiners. 

